Elongate levers used on control systems are susceptible to breakage caused by inadvertent impact. For example, motorcycles and bicycles are susceptible to spills and falls, particularly when being used in a race or off-road. The familiar brake and clutch cable control lever assemblies on a motorcycle, which are mounted on the front of the motorcycle handlebars, are particularly vulnerable to impact and fracture during these incidents, even during relatively minor spills and falls. Similarly, motorcycle drivers themselves can be injured during a spill or fall by impact with these lever assemblies.
A broken brake or clutch lever assembly arising during a spill renders an otherwise functional motorcycle inoperative. Such an incident can be particularly troublesome during a race, where time lost replacing a broken lever assembly will usually result in losing the race, or during off-road operations, where assistance is usually a great distance away.
Several inventors have recognized this problem and attempted to solve it. For example, see U.S. Pat. No. 4,088,040 to Ross-Myring, U.S. Pat. No. 4,726,252 to Dawson, and U.S. Pat. No. 4,730,509 to Homady. In general, they have attempted to solve this problem in one of the following three ways.
One attempted improvement involves designing a lever handle that toggles in any direction with respect to a base extending from the motorcycle handlebar. An example of this attempted improvement may be found in U.S. Pat. No. 4,088,040 to Ross-Myring. Unfortunately, the increased range of motion of these types of levers prevents them from having a clearly defined control motion during use. Such lack of a defined control motion adversely affects the controllability of the lever.
A second attempted improvement involves allowing the lever to breakaway from its mount during impact. One such improvement is described in U.S. Pat. No. 4,730,509 to Hornady. In general, with these types of devices, the lever handle is detachably secured to a base at its pivot point such that it detaches from the base upon impact. However, considerable user time and attention is required to reinstall the lever handle on the base. Moreover, because the lever handle is completely detached from the base on impact, there is an increased risk of outright losing the detached lever in mud or other adverse terrain during the spill or fall.
Finally, some inventors have attempted to overcome the problems with known control lever systems by providing a second axis of rotation to the lever. U.S. Pat. No. 4,726,252 to Dawson is an example of this type of attempted improvement. In general, in addition to the typical pivot axis, about which the lever is rotated to actuate the control cable, the handle assembly has a second axis of rotation, usually biased to a neutral operational position, to deflect the lever assembly on impact.
However, several problems with these types of lever assemblies have arisen. First, because only one additional axis of rotation is provided, the ability of the lever handle to absorb the impact by deflecting about this second axis depends on the actual direction of force applied to the lever assembly by the impact. In many cases, the force of the impact is aligned with the second axis of rotation precluding the handle lever from rotating about this axis on impact. Second, the known means for allowing the handle lever to pivot about an axis are prone to fill with water, dirt, and debris, further inhibiting their ability to function properly on impact. Third, these known pivot designs are prone to become easily displaced from their neutral operational position, even during normal operation, thereby adversely impacting the controllability of the motorcycle during critical times such as racing and off-road operations. And fourth, many of the known designs are bulky devices that are not easily retrofit into the existing control lever pivot bases installed on most motorcycles.
Accordingly, despite the attempted improvements, there remains a need for a collapsible control lever system with a defined control motion during normal operation that is able to absorb a wide variety of impacts without breaking and quickly restore itself to its working configuration following impact.